Biological Research Centre, Institute of Biophysics, Hungarian Academy of Sciences, Temesvári krt. 62, 6726, Szeged, Hungary.
Eur Biophys J. 2013 Mar;42(2-3):159-68. doi: 10.1007/s00249-012-0812-x. Epub 2012 Apr 20.
Cytochrome b561 (Cyt-b561) proteins constitute a family of trans-membrane proteins that are present in a wide variety of organisms. Two of their characteristic properties are the reducibility by ascorbate (ASC) and the presence of two distinct b-type hemes localized on two opposite sides of the membrane. Here we show that the tonoplast-localized and the putative tumor suppressor Cyt-b561 proteins can be reduced by other reductants than ASC and dithionite. A detailed spectral analysis of the ASC-dependent and dihydrolipoic acid (DHLA)-dependent reduction of these two Cyt-b561 proteins is also presented. Our results are discussed in relation to the known antioxidant capability of DHLA as well as its role in the regeneration of other antioxidant compounds of cells. These results allow us to speculate on new biological functions for the trans-membrane Cyt-b561 proteins.
细胞色素 b561（Cyt-b561）蛋白构成了一个跨膜蛋白家族，存在于多种生物体中。它们的两个特征性质是能够被抗坏血酸（ASC）还原，以及存在两个位于膜两侧的不同 b 型血红素。在这里，我们表明质膜定位的和假定的肿瘤抑制因子 Cyt-b561 蛋白可以被 ASC 和连二亚硫酸盐以外的其他还原剂还原。还呈现了对这两种 Cyt-b561 蛋白的 ASC 依赖性和二氢硫辛酸（DHLA）依赖性还原的详细光谱分析。我们的结果与已知的 DHLA 的抗氧化能力及其在细胞内其他抗氧化化合物再生中的作用有关。这些结果使我们能够推测跨膜 Cyt-b561 蛋白的新生物学功能。
